Between November 2014 and October 2015, Meriton Serviced Apartments either withheld or falsified the contact details of customers it thought might be critical, Federal Court Justice Mark Moshinsky said in a written judgment.

The company’s booking software allowed staff to add letters to customers’ email addresses to stop TripAdvisor reaching them if they had made complaints, he said.

The company also refrained from passing on customer details during periods of hotel renovations or maintenance, which reduced the number of negative reviews of Meriton properties on the TripAdvisor website.

In court, internal emails tendered as evidence showed senior Meriton staff reminding other workers that negative reviews “could have been prevented” if customer emails were “masked” before being sent to TripAdvisor.

The company was found to have breached Australian competition law and would be fined an amount yet to be determined.

Meriton disputed that the practice had any effect on its TripAdvisor rating and said it was considering its legal options.

The company stopped withholding customers details as soon Triguboff - who was rated Australia’s wealthiest man in 2016 - found out, it said in a statement on Friday.

The Australian Competition and Consumer Commission (ACCC), which brought the proceedings against Meriton, said it was “vital” reviews for TripAdvisor were not manipulated.

“In reducing the chances of a customer posting a negative review, Meriton created a more positive or favourable impression of the quality or amenity of the Meriton properties on the TripAdvisor website,” ACCC Commisioner Sarah Court said in a statement. (Reporting by Will Ziebell; Editing by Stephen Coates)